Wrench having an extension handle associated with measuring indicia



o. T. BLUNT 2,964,981 WRENCH HAVING AN EXTENSION HANDLE ASSOCIATED WITH MEASURING INDICIA Filed Feb. 27. 1959 Dec. 20, 1960 OWEN T BLU/VT IN VENTOR.

W fa BY A TTO RNEVS' United States Patent WRENCH HAVING AN EXTENSION HANDLE ASSOCIATED WITH MEASURING INDICIA Owen T. Blunt, Bloomfield Hills, Mi'ch., assignor to Ford Motor Company, Dearboru, Mich., a corporation of Delaware Filed Feb. 27, 1959, Ser. No. 796,084

4 Claims. (Cl. 81-477) My invention relates generally to a new and improved wrench and more particularly to a torque wrench of relatively high torque capacity. My improved torque wrench is particularly adapted to be used in assembly operations for tightening threaded nuts on studs. For example, the wrench of my instant invention is useful in truck manufacturing operations for tightening large truck wheel lug nuts.

. According to a principal'feature of my invention. provision is made for lim ting the torque which may be applied to a threaded nut so that a desired stress will be develoned under all conditions.

The provision of an improved torque wrench of the type above mentioned being a principal object of my invention, it is another object of my invention to provide a torque wrench with a torque arm of variable length so that the torque developed b the wrench may be varied as desired for any given appl ed force. ,This avoids understressing as well as over-stressing.

It is a further obiect of my invention to provide a new and improved torque wrench of the type above set forth which is character zed b i s s mplified construction and which may be readily adiusted by means of a simple manual operation to any desired torque capacity within a wide range of limits.

It is a further obiect of my invention to provide a heavy duty torque wrench for use in those a plications requiring a developed torque in excess of 400 lbs-ft. and

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is applied to body portion 14 in one direction. However, 'when a turning moment is applied in the opposite direction, the clutch mechanism will overrun adapter 16.

The adapter.16 is capable of retaining sockets for gripping polygonally spaced nuts and bolt heads. This headpiece construction is conventional and well-known, and for this reason the specific construction of the in- I ternal one-way clutch mechanism for the headpiece will which is substantia ly more durab e than high capacity tor ue wrenches of known construction.

Other obiects and advanta es of m m roved torque wrench w ll become app rent from the following description and from the accompanying drawin s. wherein:

Figure 1 is a side elevat on view, partly in section, of my improved torque wrench;

Figure 2 is a side elevation view of a portion of the wrench assembly shown in Figure 1;

Figure 3 is a side elevation view of my improved wrench assembly as viewed from the plane of section line 33 of Figure 1;

Figure 4 is a deta led cross sectional view taken along section line 44 of Figure l; and

Figure 5 is a cross sectional view taken along section line 55 of Figure 1.

Referring first to Figure 1, the wrench of my instant invention comprises a headpiece 10 and a lever arm generally designated by numeral 12. Headpiece 10 may be of conventional construction and it includes a body portion 14 and a socket retainer or adapter 16, the latter preferably being of square cross section and extending outwardly from the body portion 14. The adapter 16 is formed with a circular base 18 which is in turn received within a cooperating circular opening formed in body portion 14. A suitable one-way ratchet or clutch mechanism is included within body portion 14 for establishing a one-way driving connection between the circular piece 18 of adapter 16 and body portion 14 so that torque may be applied to adapter 16 when a turning moment not be described at this time.

The lever arm 12 comprises two principal portions separately identified by numerals 20 and 22, the former being fixed to the body portion 14 of headpiece 10. Lever arm portion 22 is telescopically received over lever arm portion 20 and is hollow to permit relative sliding movement between the lever arm portions.

Lever arm portion 22 is formed with a tubular or circular cross section, and leyer arm portion 20 is formed with a circular cross sectional shape, although I contemplate that other cross sectional forms can also be employed.

Figures 1 and 3 show a set screw 24 having a wing portion 26 to accommodate a manual adjustment of the same. Screw 24 is threadably received in a nut 28 which in turn is welded or otherwise fixed to the exterior of lever arm portion 22. The lever arm portion 20 is recessed at regularly spaced intervals as shown at 30 and the end of screw 24 is adapted to be seated in the recesses 30 thereby locking lever arm portion 20 to lever arm portion 22. By preference, the lever arm portion 22 is formed with a tapped opening which forms a continuation of the threaded opening of the nut 28.

Lever arm portion 20 may carry thereon a plurality of indicia, one indicium corresponding to each recess 30. One end of lever arm portion 22 selectively registers with the indicia as indicated. 1 1

A stirrup or treadle is pivotally secured at the end of lever arm portion 22. An extension 32 is received within the opening at the end of lever arm portion 22 and it may be fixed therein by weld metal 34. As best seen in Figure 5, extension 32 is of rectangular cross section with chamfered corners. The stirrup is generally designated by numeral 36 and it includes a bifurcated bracket having parallel arms 38 and 40 adapted to straddle extension 32. Arms 38 and 40 and the extension 32 are formed with aligned openings for receiving a pivot pin 42, said pin having a fiat head 44. The pin is formed with an opening through which a cotter pin 46 is received, and fiat washers are situated adjacent the arms 38 and 40 as indicated at 48 and 50 respectively.

The stirrup 36 further includes a treadle plate 52 having sufficient width to accommodate the sole of the operators shoe. If desired, the treadle plate 52 may be formed with cleats 54.

Bracket arms 38 and 40 may be welded or otherwise secured to the upper portion of a diverging stirrup member 56 which in turn may be welded to opposed sides of treadle plate 52.

In operation the socket carried by the headpiece 10 may be received over a lug nut and the operator may then apply torque to the lug nut by stepping on treadle plate 52. The magnitude of the torque applied to the lug nut will then be equal to the weight of the operator multiplied by the effective length of the lever arm. The indicia on the lever arm portion 20 provide an indication of the magnitude of the torque which may be developed by the wrench and the wrench may be calibrated so that the left end of the lever arm portion 22 as viewed in the drawing may be set at an indicium corresponding to the weight of the operator. For example, if the operator weighs 188 pounds, the lever arm portions will be adjusted to the relative setting indicated in Figure 1. When the operator steps on the treadle plate 52, the desired limiting torque 3 will be developed by the wrench. However, if the wrench is subsequently used by an operator weighing, for example' 140 pounds, therelative-settirig between the lev'er'arni portions 20 and 22 will be adjusted. so that-the leftend of the lever arm portion 22 will be located at the 140 pound marking. It isthus apparent that the efiective leverage of the wrench is thus increased to compensatefor the lesser weight of the operator. In this way the desired torque will be developed in each case regardless of the weight of the operator.- 7

It is thus seen that I have provided a very simplified, workable and durable torque wrench which may beadjusted as desired to produce any'desired't'orque'capacity, and the possibility of'overstressing or understressing the workpiece is eliminated.

Having-thus describedaprincipal embodiment of my invention, what I claim and. desire to secure by United States LettersPatent is:

1. In a torque wrench assembly-for applying torque to a workpiece, aheadpiece, a lever arm, said lever arm including a first portion connected to said headpiece and a second portion telescopically related with respect to said first portion and forming an extension thereof, and means for a pplying a force to the free end of said lever arm including a;treadle carried by said lever arm, said treadle being adapted to accommodate-the foot of an operator, one of said arm portions having indicia formed thereon at spaced intervals,the other arm portion selectively regi'stering with said indicia whereby the desired torque trans mitted by said assembly for a given force appliedflto said treadle may; be readily obtained.

2; In atorque wrench assembly forapplying torque to a workpiece, a headpiece, a lever arm; said'leve'r arm including a"tirstportion'connected to said headpiece-and asecondgportion telescopically relatedfwith'respect to said first portion'and forming an extension thereof, and meansfor applying a force to thefree end of said lever arm including a treadle carried by said lever arm, said treadle beingadapted to accommodate the foot oi? an operator,

erases first portion and forming an extension thereof, means for releasably locking together said lever arm portions at any desired adjusted position including a locking screw carried by one lever arm portion, longitudinally spaced recesses formed in the other? lever arm portion, said locking screw beingadapted to engage said .recessesto establish any desireddegree of? extension, and means for; applying a force to the free end of' said lever arm including a treadle carried by; said? lever. arm, said; treadle being adapted? to. accommodate the" foot of an operator, one of said arm portions having indicia formed thereo'n'at spaced intervals one end of. the 'otherarm; portion se lectively registering with said indicia, said indicia being said treadle comprising a treadle plate and a bracket secured to said treadle plate, said bracket being pivotally connected to said lever arm, one of said arm portions having indicia formed thereon at spaced intervals, the other arm portion selectively registering with said indicia whereby the desired torque transmitted by said assembly fora given .weight of the operator may be readily obtained.

3.. In a torque wrench assembly for applyingtorque to a. workpiece,ja headpiece, a lever. arm, said lever arm including a first portion connected to said headpiece and a second.portiontelescopically. related with respect to said calibrated so than a: de'sireiflimitirigi torque will be developed by the wrench assembly when said other arm portion is adjusted relative to said one arm portion to an-indicium corresponding to the weight of the operator.

4.; Imatorquewrench assembly for applying torque to a workpiece; a headpiece, a lever arm, said lever arm including a' fir'stportion connected to said headpiece and as'e'cond: portion telescopicallyrelated with respect to said first portion: andfo'rming. an extension thereof, means-for releasablyrlocking together said" lever arm portions at any desired adjusted position including a. lockingscrew carried'by one lever arm portion, indi'cia carried by the other leverarm portion at longitudinall'y'spaced positions, and means for'applyin'g a force to the free end of' said lever arm including a treadle carried by said lever arm, said treadle being adapted to' accommodate the foot of an 'p'erator; said indicia beingcalibrated so that a desired limiting torque will be devclopedby the'wrench when said one lever arm portion is adjusted relative to said other lever a'rml portion. to an indiciumcorresponding to the weight'of 'th'eoperator."

References Cited in the file of this patent ,UNlTED STATES PATENTS 

